Neuroanatomy

Question 1

What are the divisions of the NS?

Answer 1

Question 2

what are the 2 main categories of cells in CNS?

Answer 2

glia and neurons

Question 3

what is the function of satellite cells?

Answer 3

surround neuronal cell bodies

Question 4

what is the function of schwann cells?

Answer 4

myelination in PNS

Question 5

what is the function of ependymal cells?

Answer 5

line ventricles

Question 6

what is the function of microglia? (x2)

Answer 6

• phagocytosis
• scar tissue formation

Question 7

what is the function of oligodendrocytes?

Answer 7

myelination in CNS

Question 8

what is the function of astrocytes? (x2)

Answer 8

• surround synapses &capillaries
• help in potassium buffering

Question 9

what are the different types of cell in CNS?

Answer 9

Question 10

are neurons excitable or non excitable?

Answer 10

excitable

Question 11

are glia excitable or non-excitable cells?

Answer 11

non-excitable cells

Question 12

how are neuron impulses carried out and in what direction?

Answer 12

impulses carried out as AP’s, which can travel only in one direction from cell body to synaptic terminal

Question 13

what does a neuron look like?

Answer 13

Question 14

describe the main features of a typical neuron (5)

Answer 14

• multiple dendrites, one axon
• nucleus –> loose chromatin, prominent nucleolus
• high metabolic rate
• cytoplasm in cell body is called perikaryon and in axon is called axoplasm
• long living and amitotic

Question 15

if there is injury to the neuron, what might happen in the long term to it?

Answer 15

axon can grow back, but if there is injury to cell body, loss is irreversible

Question 16

how is the myelin sheath formed in the PNS?

Answer 16

by schwann cells

Question 17

how is the myelin sheath formed in the CNS?

Answer 17

by oligodendrocytes

Question 18

what is the effect of the myelin sheath?

Answer 18

increases the conduction speed in axons by ‘saltatory conduction’

Question 19

what is the myelin sheath exactly?

Answer 19

nothing but a cell membrane

Question 20

describe the process of myelination of axons

Answer 20

• schwann cells wrap around myelinated axons and a mesoaxon is formed
• cytoplasm of schwann cell is extruded, leaving only cell membrane

Question 21

what happens to the myelination of non-myelinated axons in PNS?

Answer 21

-non-myelinated axons in PNS still get wrapped by schwann cells but myelin sheath isn’t formed

Question 22

What are the 3 main types of neurons?

Answer 22

• multipolar
• bipolar
• pseudounipolar

Question 23

What kind of neurons make up multipolar neurons?

Answer 23

• motor neurons
• interneurons

Question 24

what kind of neurons make up bipolar neurons?

Answer 24

special senses neurons:

• olfactory mucosa
• retinal nerve fibres

Question 25

what kind of neurons make up psuedounipolar neurons?

Answer 25

all sensory neurons in PNS

Question 26

what do they look like?

Answer 26

Question 27

describe multipolar neurons

Answer 27

-type of neuron that possesses a single axon and many dendrites

Question 28

describe bipolar neurons

Answer 28

-has 2 cytoplasmic extensions attached to cell body -one serves as the axon and the other as the dendrite

Question 29

describe pseudounipolar neurons

Answer 29

-one axon that splits into 2 branches –> one that goes to periphery and other to spinal cord

Question 30

In CNS:

-what is the collection of cell bodies + non-myelinated axons called?

Answer 30

• grey matter (if diffuse)
• nuclei (if localised)

Question 31

In CNS:

-what does the collection of myelinated axons form?

Answer 31

white matter or tracts

Question 32

what are tracts?

Answer 32

bundles of axons carrying information within the white matter

Question 33

In PNS:

-what do myelinated axons form?

Answer 33

nerves

Question 34

In PNS:

-what do cell bodies (grey matter) form?

Answer 34

ganglia

Question 35

Answer 35

1. Pseudounipolar neuron
2. Ganglion
3. Tracts- white matter
4. Nucleus